1. Field of the Invention
The present invention relates to an electromagnetic starter switch for starting an internal combustion engine by means of a pinion driven by a motor.
2. Description of the Related Art
Conventionally, in electromagnetic starter switches, in order to control action of a motor during starting so as to be divided into two phases, there is provided: a main fixed contact; a main movable contact coming into contact with the main fixed contact; an auxiliary fixed contact; and an auxiliary movable contact coming into contact with the auxiliary fixed contact, a resistor being installed in series in a circuit formed when the auxiliary movable contact comes into contact with the auxiliary fixed contact such that an electric current from a battery flows through this closed circuit to an armature of the motor, rotating the armature at low speed to intermesh a pinion linked to the clutch with a ring gear.
Then, in a circuit formed when the main movable contact comes into contact with the main fixed contact, electric current from the battery flows through this closed circuit directly to the armature of the motor, and the motor rotates at a rated speed due to application of a rated voltage, starting an internal combustion engine. (See Patent Literature 1, for example.)
Patent Literature 1
Japanese Patent Laid-Open No. 2004-190544 (Gazette)
In an electromagnetic starter switch having the above configuration, after the auxiliary movable contact comes into contact with the auxiliary fixed contact, rotating the armature at low speed to intermesh the pinion fixed to the shaft of the motor with the ring gear, electric current from the battery should flow through the armature of the motor directly when the main movable contact comes into contact with the main fixed contact, but if for some reason the main movable contact does not come into contact with the main fixed contact, one problem has been that the temperature of the resistor may rise abnormally since electric current continues to flow through the resistor.